The invention relates to the technical field of platemaking, and discloses a device capable of solving the problem of discontinuous ink output or unclear printing during platemaking of a packaging bag. The device comprises a supporting seat, a connecting column is supported by the supporting seat, and the lower part of the supporting seat is fixedly connected with the connecting column. Through the cooperation use of an ink storage box, a push rod, a swing rod and a fourth turntable, ink can be continuously output during use, printing discontinuity caused by insufficient ink output during platemaking printing is avoided, repeated ink adding is avoided, more time and labor are saved, through cooperative use of a moving block, a second rotary disc and a third rotary disc, the packaging bag is in a stable state during platemaking printing, so that ghosting caused by poor stability during printing is avoided, the stability during printing is improved, printing is clearer, and through cooperative use of the moving block, the second rotating disc and the third rotating disc, a brush head uniformly brushes the upper portion of a template during printing, so that brushing is more uniform.